/* * Copyright (c) 1994 by Xerox Corporation. All rights reserved. * Copyright (c) 1996 by Silicon Graphics. All rights reserved. * Copyright (c) 1998 by Fergus Henderson. All rights reserved. * Copyright (c) 2000-2005 by Hewlett-Packard Company. All rights reserved. * Copyright (c) 2008-2021 Ivan Maidanski * * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. * * Permission is hereby granted to use or copy this program * for any purpose, provided the above notices are retained on all copies. * Permission to modify the code and to distribute modified code is granted, * provided the above notices are retained, and a notice that the code was * modified is included with the above copyright notice. */ #include "private/pthread_support.h" /* * Support code originally for LinuxThreads, the clone()-based kernel * thread package for Linux which is included in libc6. * * This code no doubt makes some assumptions beyond what is * guaranteed by the pthread standard, though it now does * very little of that. It now also supports NPTL, and many * other Posix thread implementations. We are trying to merge * all flavors of pthread support code into this file. */ #if defined(GC_PTHREADS) && !defined(GC_WIN32_THREADS) # include # include # include # include # include # include # if !defined(SN_TARGET_ORBIS) && !defined(SN_TARGET_PSP2) # if !defined(GC_RTEMS_PTHREADS) # include # endif # include # include # include # include # endif # include # include "gc_inline.h" #if defined(GC_DARWIN_THREADS) # include "private/darwin_semaphore.h" #else # include #endif /* !GC_DARWIN_THREADS */ #if defined(GC_DARWIN_THREADS) || defined(GC_FREEBSD_THREADS) # include #endif /* GC_DARWIN_THREADS */ #if defined(GC_NETBSD_THREADS) || defined(GC_OPENBSD_THREADS) # include # include #endif /* GC_NETBSD_THREADS */ /* Allocator lock definitions. */ #if !defined(USE_SPIN_LOCK) GC_INNER pthread_mutex_t GC_allocate_ml = PTHREAD_MUTEX_INITIALIZER; #endif #ifdef GC_ASSERTIONS GC_INNER unsigned long GC_lock_holder = NO_THREAD; /* Used only for assertions. */ #endif #if defined(GC_DGUX386_THREADS) # include # include /* sem_t is an uint in DG/UX */ typedef unsigned int sem_t; #endif /* GC_DGUX386_THREADS */ /* Undefine macros used to redirect pthread primitives. */ # undef pthread_create # ifndef GC_NO_PTHREAD_SIGMASK # undef pthread_sigmask # endif # ifndef GC_NO_PTHREAD_CANCEL # undef pthread_cancel # endif # ifdef GC_HAVE_PTHREAD_EXIT # undef pthread_exit # endif # undef pthread_join # undef pthread_detach # if defined(GC_OSF1_THREADS) && defined(_PTHREAD_USE_MANGLED_NAMES_) \ && !defined(_PTHREAD_USE_PTDNAM_) /* Restore the original mangled names on Tru64 UNIX. */ # define pthread_create __pthread_create # define pthread_join __pthread_join # define pthread_detach __pthread_detach # ifndef GC_NO_PTHREAD_CANCEL # define pthread_cancel __pthread_cancel # endif # ifdef GC_HAVE_PTHREAD_EXIT # define pthread_exit __pthread_exit # endif # endif #ifdef GC_USE_LD_WRAP # define WRAP_FUNC(f) __wrap_##f # define REAL_FUNC(f) __real_##f int REAL_FUNC(pthread_create)(pthread_t *, GC_PTHREAD_CREATE_CONST pthread_attr_t *, void *(*start_routine)(void *), void *); int REAL_FUNC(pthread_join)(pthread_t, void **); int REAL_FUNC(pthread_detach)(pthread_t); # ifndef GC_NO_PTHREAD_SIGMASK int REAL_FUNC(pthread_sigmask)(int, const sigset_t *, sigset_t *); # endif # ifndef GC_NO_PTHREAD_CANCEL int REAL_FUNC(pthread_cancel)(pthread_t); # endif # ifdef GC_HAVE_PTHREAD_EXIT void REAL_FUNC(pthread_exit)(void *) GC_PTHREAD_EXIT_ATTRIBUTE; # endif #else # ifdef GC_USE_DLOPEN_WRAP # include # define WRAP_FUNC(f) f # define REAL_FUNC(f) GC_real_##f /* We define both GC_f and plain f to be the wrapped function. */ /* In that way plain calls work, as do calls from files that */ /* included gc.h, which redefined f to GC_f. */ /* FIXME: Needs work for DARWIN and True64 (OSF1) */ typedef int (* GC_pthread_create_t)(pthread_t *, GC_PTHREAD_CREATE_CONST pthread_attr_t *, void * (*)(void *), void *); static GC_pthread_create_t REAL_FUNC(pthread_create); # ifndef GC_NO_PTHREAD_SIGMASK typedef int (* GC_pthread_sigmask_t)(int, const sigset_t *, sigset_t *); static GC_pthread_sigmask_t REAL_FUNC(pthread_sigmask); # endif typedef int (* GC_pthread_join_t)(pthread_t, void **); static GC_pthread_join_t REAL_FUNC(pthread_join); typedef int (* GC_pthread_detach_t)(pthread_t); static GC_pthread_detach_t REAL_FUNC(pthread_detach); # ifndef GC_NO_PTHREAD_CANCEL typedef int (* GC_pthread_cancel_t)(pthread_t); static GC_pthread_cancel_t REAL_FUNC(pthread_cancel); # endif # ifdef GC_HAVE_PTHREAD_EXIT typedef void (* GC_pthread_exit_t)(void *) GC_PTHREAD_EXIT_ATTRIBUTE; static GC_pthread_exit_t REAL_FUNC(pthread_exit); # endif # else # define WRAP_FUNC(f) GC_##f # if !defined(GC_DGUX386_THREADS) # define REAL_FUNC(f) f # else /* GC_DGUX386_THREADS */ # define REAL_FUNC(f) __d10_##f # endif /* GC_DGUX386_THREADS */ # endif #endif #if defined(GC_USE_LD_WRAP) || defined(GC_USE_DLOPEN_WRAP) /* Define GC_ functions as aliases for the plain ones, which will */ /* be intercepted. This allows files which include gc.h, and hence */ /* generate references to the GC_ symbols, to see the right symbols. */ GC_API int GC_pthread_create(pthread_t * t, GC_PTHREAD_CREATE_CONST pthread_attr_t *a, void * (* fn)(void *), void * arg) { return pthread_create(t, a, fn, arg); } # ifndef GC_NO_PTHREAD_SIGMASK GC_API int GC_pthread_sigmask(int how, const sigset_t *mask, sigset_t *old) { return pthread_sigmask(how, mask, old); } # endif /* !GC_NO_PTHREAD_SIGMASK */ GC_API int GC_pthread_join(pthread_t t, void **res) { return pthread_join(t, res); } GC_API int GC_pthread_detach(pthread_t t) { return pthread_detach(t); } # ifndef GC_NO_PTHREAD_CANCEL GC_API int GC_pthread_cancel(pthread_t t) { return pthread_cancel(t); } # endif /* !GC_NO_PTHREAD_CANCEL */ # ifdef GC_HAVE_PTHREAD_EXIT GC_API GC_PTHREAD_EXIT_ATTRIBUTE void GC_pthread_exit(void *retval) { pthread_exit(retval); } # endif #endif /* Linker-based interception. */ #ifdef GC_USE_DLOPEN_WRAP STATIC GC_bool GC_syms_initialized = FALSE; STATIC void GC_init_real_syms(void) { void *dl_handle; if (GC_syms_initialized) return; # ifdef RTLD_NEXT dl_handle = RTLD_NEXT; # else dl_handle = dlopen("libpthread.so.0", RTLD_LAZY); if (NULL == dl_handle) { dl_handle = dlopen("libpthread.so", RTLD_LAZY); /* without ".0" */ } if (NULL == dl_handle) ABORT("Couldn't open libpthread"); # endif REAL_FUNC(pthread_create) = (GC_pthread_create_t)(word) dlsym(dl_handle, "pthread_create"); # ifdef RTLD_NEXT if (REAL_FUNC(pthread_create) == 0) ABORT("pthread_create not found" " (probably -lgc is specified after -lpthread)"); # endif # ifndef GC_NO_PTHREAD_SIGMASK REAL_FUNC(pthread_sigmask) = (GC_pthread_sigmask_t)(word) dlsym(dl_handle, "pthread_sigmask"); # endif REAL_FUNC(pthread_join) = (GC_pthread_join_t)(word) dlsym(dl_handle, "pthread_join"); REAL_FUNC(pthread_detach) = (GC_pthread_detach_t)(word) dlsym(dl_handle, "pthread_detach"); # ifndef GC_NO_PTHREAD_CANCEL REAL_FUNC(pthread_cancel) = (GC_pthread_cancel_t)(word) dlsym(dl_handle, "pthread_cancel"); # endif # ifdef GC_HAVE_PTHREAD_EXIT REAL_FUNC(pthread_exit) = (GC_pthread_exit_t)(word) dlsym(dl_handle, "pthread_exit"); # endif GC_syms_initialized = TRUE; } # define INIT_REAL_SYMS() if (EXPECT(GC_syms_initialized, TRUE)) {} \ else GC_init_real_syms() #else # define INIT_REAL_SYMS() (void)0 #endif static GC_bool parallel_initialized = FALSE; #if defined(MPROTECT_VDB) && defined(DARWIN) GC_INNER int GC_inner_pthread_create(pthread_t *t, GC_PTHREAD_CREATE_CONST pthread_attr_t *a, void *(*fn)(void *), void *arg) { INIT_REAL_SYMS(); return REAL_FUNC(pthread_create)(t, a, fn, arg); } #endif #ifndef GC_ALWAYS_MULTITHREADED GC_INNER GC_bool GC_need_to_lock = FALSE; #endif STATIC int GC_nprocs = 1; /* Number of processors. We may not have */ /* access to all of them, but this is as good */ /* a guess as any ... */ #ifdef THREAD_LOCAL_ALLOC /* We must explicitly mark ptrfree and gcj free lists, since the free */ /* list links wouldn't otherwise be found. We also set them in the */ /* normal free lists, since that involves touching less memory than */ /* if we scanned them normally. */ GC_INNER void GC_mark_thread_local_free_lists(void) { int i; GC_thread p; for (i = 0; i < THREAD_TABLE_SZ; ++i) { for (p = GC_threads[i]; 0 != p; p = p -> next) { if (!(p -> flags & FINISHED)) GC_mark_thread_local_fls_for(&(p->tlfs)); } } } # if defined(GC_ASSERTIONS) /* Check that all thread-local free-lists are completely marked. */ /* Also check that thread-specific-data structures are marked. */ void GC_check_tls(void) { int i; GC_thread p; for (i = 0; i < THREAD_TABLE_SZ; ++i) { for (p = GC_threads[i]; 0 != p; p = p -> next) { if (!(p -> flags & FINISHED)) GC_check_tls_for(&(p->tlfs)); } } # if defined(USE_CUSTOM_SPECIFIC) if (GC_thread_key != 0) GC_check_tsd_marks(GC_thread_key); # endif } # endif /* GC_ASSERTIONS */ #endif /* THREAD_LOCAL_ALLOC */ # ifndef MAX_MARKERS # define MAX_MARKERS 16 # endif #ifdef PARALLEL_MARK static ptr_t marker_sp[MAX_MARKERS - 1] = {0}; #ifdef IA64 static ptr_t marker_bsp[MAX_MARKERS - 1] = {0}; #endif #if defined(GC_DARWIN_THREADS) && !defined(GC_NO_THREADS_DISCOVERY) static mach_port_t marker_mach_threads[MAX_MARKERS - 1] = {0}; /* Used only by GC_suspend_thread_list(). */ GC_INNER GC_bool GC_is_mach_marker(thread_act_t thread) { int i; for (i = 0; i < GC_markers_m1; i++) { if (marker_mach_threads[i] == thread) return TRUE; } return FALSE; } #endif /* GC_DARWIN_THREADS */ #ifdef HAVE_PTHREAD_SETNAME_NP_WITH_TID_AND_ARG /* NetBSD */ static void set_marker_thread_name(unsigned id) { int err = pthread_setname_np(pthread_self(), "GC-marker-%zu", (void*)(size_t)id); if (err != 0) WARN("pthread_setname_np failed, errno= %" WARN_PRIdPTR "\n", (signed_word)err); } #elif defined(HAVE_PTHREAD_SETNAME_NP_WITH_TID) \ || defined(HAVE_PTHREAD_SETNAME_NP_WITHOUT_TID) static void set_marker_thread_name(unsigned id) { char name_buf[16]; /* pthread_setname_np may fail for longer names */ int len = sizeof("GC-marker-") - 1; /* Compose the name manually as snprintf may be unavailable or */ /* "%u directive output may be truncated" warning may occur. */ BCOPY("GC-marker-", name_buf, len); if (id >= 10) name_buf[len++] = (char)('0' + (id / 10) % 10); name_buf[len] = (char)('0' + id % 10); name_buf[len + 1] = '\0'; # ifdef HAVE_PTHREAD_SETNAME_NP_WITHOUT_TID /* iOS, OS X */ (void)pthread_setname_np(name_buf); # else /* Linux, Solaris, etc. */ if (pthread_setname_np(pthread_self(), name_buf) != 0) WARN("pthread_setname_np failed\n", 0); # endif } #else # define set_marker_thread_name(id) (void)(id) #endif STATIC void * GC_mark_thread(void * id) { word my_mark_no = 0; IF_CANCEL(int cancel_state;) if ((word)id == GC_WORD_MAX) return 0; /* to prevent a compiler warning */ DISABLE_CANCEL(cancel_state); /* Mark threads are not cancellable; they */ /* should be invisible to client. */ set_marker_thread_name((unsigned)(word)id); marker_sp[(word)id] = GC_approx_sp(); # ifdef IA64 marker_bsp[(word)id] = GC_save_regs_in_stack(); # endif # if defined(GC_DARWIN_THREADS) && !defined(GC_NO_THREADS_DISCOVERY) marker_mach_threads[(word)id] = mach_thread_self(); # endif /* Inform GC_start_mark_threads about completion of marker data init. */ GC_acquire_mark_lock(); if (0 == --GC_fl_builder_count) /* count may have a negative value */ GC_notify_all_builder(); for (;; ++my_mark_no) { /* GC_mark_no is passed only to allow GC_help_marker to terminate */ /* promptly. This is important if it were called from the signal */ /* handler or from the GC lock acquisition code. Under Linux, it's */ /* not safe to call it from a signal handler, since it uses mutexes */ /* and condition variables. Since it is called only here, the */ /* argument is unnecessary. */ if (my_mark_no < GC_mark_no || my_mark_no > GC_mark_no + 2) { /* resynchronize if we get far off, e.g. because GC_mark_no */ /* wrapped. */ my_mark_no = GC_mark_no; } # ifdef DEBUG_THREADS GC_log_printf("Starting mark helper for mark number %lu\n", (unsigned long)my_mark_no); # endif GC_help_marker(my_mark_no); } } STATIC pthread_t GC_mark_threads[MAX_MARKERS]; #ifdef GLIBC_2_1_MUTEX_HACK /* Ugly workaround for a linux threads bug in the final versions */ /* of glibc2.1. Pthread_mutex_trylock sets the mutex owner */ /* field even when it fails to acquire the mutex. This causes */ /* pthread_cond_wait to die. Remove for glibc2.2. */ /* According to the man page, we should use */ /* PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP, but that isn't actually */ /* defined. */ static pthread_mutex_t mark_mutex = {0, 0, 0, PTHREAD_MUTEX_ERRORCHECK_NP, {0, 0}}; #else static pthread_mutex_t mark_mutex = PTHREAD_MUTEX_INITIALIZER; #endif static int available_markers_m1 = 0; #ifdef CAN_HANDLE_FORK static pthread_cond_t mark_cv; /* initialized by GC_start_mark_threads_inner */ #else static pthread_cond_t mark_cv = PTHREAD_COND_INITIALIZER; #endif STATIC void GC_wait_for_gc_completion(GC_bool wait_for_all); GC_INNER void GC_start_mark_threads_inner(void) { int i; pthread_attr_t attr; # ifndef NO_MARKER_SPECIAL_SIGMASK sigset_t set, oldset; # endif GC_ASSERT(I_HOLD_LOCK()); ASSERT_CANCEL_DISABLED(); if (available_markers_m1 <= 0 || GC_parallel) return; /* Skip if parallel markers disabled or already started. */ GC_wait_for_gc_completion(TRUE); # ifdef CAN_HANDLE_FORK /* Initialize mark_cv (for the first time), or cleanup its value */ /* after forking in the child process. All the marker threads in */ /* the parent process were blocked on this variable at fork, so */ /* pthread_cond_wait() malfunction (hang) is possible in the */ /* child process without such a cleanup. */ /* TODO: This is not portable, it is better to shortly unblock */ /* all marker threads in the parent process at fork. */ { pthread_cond_t mark_cv_local = PTHREAD_COND_INITIALIZER; BCOPY(&mark_cv_local, &mark_cv, sizeof(mark_cv)); } # endif GC_ASSERT(GC_fl_builder_count == 0); INIT_REAL_SYMS(); /* for pthread_create */ if (0 != pthread_attr_init(&attr)) ABORT("pthread_attr_init failed"); if (0 != pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED)) ABORT("pthread_attr_setdetachstate failed"); # ifdef DEFAULT_STACK_MAYBE_SMALL /* Default stack size is usually too small: increase it. */ /* Otherwise marker threads or GC may run out of space. */ { size_t old_size; if (pthread_attr_getstacksize(&attr, &old_size) != 0) ABORT("pthread_attr_getstacksize failed"); if (old_size < MIN_STACK_SIZE && old_size != 0 /* stack size is known */) { if (pthread_attr_setstacksize(&attr, MIN_STACK_SIZE) != 0) ABORT("pthread_attr_setstacksize failed"); } } # endif /* DEFAULT_STACK_MAYBE_SMALL */ # ifndef NO_MARKER_SPECIAL_SIGMASK /* Apply special signal mask to GC marker threads, and don't drop */ /* user defined signals by GC marker threads. */ if (sigfillset(&set) != 0) ABORT("sigfillset failed"); # if !defined(GC_DARWIN_THREADS) && !defined(GC_OPENBSD_UTHREADS) \ && !defined(NACL) /* These are used by GC to stop and restart the world. */ if (sigdelset(&set, GC_get_suspend_signal()) != 0 || sigdelset(&set, GC_get_thr_restart_signal()) != 0) ABORT("sigdelset failed"); # endif if (REAL_FUNC(pthread_sigmask)(SIG_BLOCK, &set, &oldset) < 0) { WARN("pthread_sigmask set failed, no markers started\n", 0); GC_markers_m1 = 0; (void)pthread_attr_destroy(&attr); return; } # endif /* !NO_MARKER_SPECIAL_SIGMASK */ /* To have proper GC_parallel value in GC_help_marker. */ GC_markers_m1 = available_markers_m1; for (i = 0; i < available_markers_m1; ++i) { if (0 != REAL_FUNC(pthread_create)(GC_mark_threads + i, &attr, GC_mark_thread, (void *)(word)i)) { WARN("Marker thread creation failed\n", 0); /* Don't try to create other marker threads. */ GC_markers_m1 = i; break; } } # ifndef NO_MARKER_SPECIAL_SIGMASK /* Restore previous signal mask. */ if (REAL_FUNC(pthread_sigmask)(SIG_SETMASK, &oldset, NULL) < 0) { WARN("pthread_sigmask restore failed\n", 0); } # endif (void)pthread_attr_destroy(&attr); GC_wait_for_markers_init(); GC_COND_LOG_PRINTF("Started %d mark helper threads\n", GC_markers_m1); } #endif /* PARALLEL_MARK */ GC_INNER GC_bool GC_thr_initialized = FALSE; GC_INNER volatile GC_thread GC_threads[THREAD_TABLE_SZ] = {0}; /* It may not be safe to allocate when we register the first thread. */ /* As "next" and "status" fields are unused, no need to push this */ /* (but "backing_store_end" field should be pushed on E2K). */ static struct GC_Thread_Rep first_thread; void GC_push_thread_structures(void) { GC_ASSERT(I_HOLD_LOCK()); GC_push_all((/* no volatile */ void *)&GC_threads, (ptr_t)(&GC_threads) + sizeof(GC_threads)); # ifdef E2K GC_PUSH_ALL_SYM(first_thread.backing_store_end); # endif # if defined(THREAD_LOCAL_ALLOC) && defined(USE_CUSTOM_SPECIFIC) GC_PUSH_ALL_SYM(GC_thread_key); # endif } #ifdef DEBUG_THREADS STATIC int GC_count_threads(void) { int i; int count = 0; GC_ASSERT(I_HOLD_LOCK()); for (i = 0; i < THREAD_TABLE_SZ; ++i) { GC_thread th = GC_threads[i]; while (th) { if (!(th->flags & FINISHED)) ++count; th = th->next; } } return count; } #endif /* DEBUG_THREADS */ /* Add a thread to GC_threads. We assume it wasn't already there. */ /* Caller holds allocation lock. */ STATIC GC_thread GC_new_thread(pthread_t id) { int hv = THREAD_TABLE_INDEX(id); GC_thread result; static GC_bool first_thread_used = FALSE; # ifdef DEBUG_THREADS GC_log_printf("Creating thread %p\n", (void *)id); for (result = GC_threads[hv]; result != NULL; result = result->next) if (!THREAD_EQUAL(result->id, id)) { GC_log_printf("Hash collision at GC_threads[%d]\n", hv); break; } # endif GC_ASSERT(I_HOLD_LOCK()); if (!EXPECT(first_thread_used, TRUE)) { result = &first_thread; first_thread_used = TRUE; GC_ASSERT(NULL == GC_threads[hv]); # if defined(THREAD_SANITIZER) && defined(CPPCHECK) GC_noop1((unsigned char)result->dummy[0]); # endif } else { result = (struct GC_Thread_Rep *) GC_INTERNAL_MALLOC(sizeof(struct GC_Thread_Rep), NORMAL); if (result == 0) return(0); } result -> id = id; # ifdef USE_TKILL_ON_ANDROID result -> kernel_id = gettid(); # endif result -> next = GC_threads[hv]; GC_threads[hv] = result; # ifdef NACL GC_nacl_gc_thread_self = result; GC_nacl_initialize_gc_thread(); # endif GC_ASSERT(result -> flags == 0 && result -> thread_blocked == 0); if (EXPECT(result != &first_thread, TRUE)) GC_dirty(result); return(result); } /* Delete a thread from GC_threads. We assume it is there. */ /* (The code intentionally traps if it wasn't.) */ /* It is safe to delete the main thread. */ STATIC void GC_delete_thread(pthread_t id) { int hv = THREAD_TABLE_INDEX(id); GC_thread p = GC_threads[hv]; GC_thread prev = NULL; # ifdef DEBUG_THREADS GC_log_printf("Deleting thread %p, n_threads= %d\n", (void *)id, GC_count_threads()); # endif GC_ASSERT(I_HOLD_LOCK()); while (!THREAD_EQUAL(p -> id, id)) { prev = p; p = p -> next; } if (prev == 0) { GC_threads[hv] = p -> next; } else { GC_ASSERT(prev != &first_thread); prev -> next = p -> next; GC_dirty(prev); } if (p != &first_thread) { # ifdef GC_DARWIN_THREADS mach_port_deallocate(mach_task_self(), p->stop_info.mach_thread); # endif GC_INTERNAL_FREE(p); } } /* If a thread has been joined, but we have not yet */ /* been notified, then there may be more than one thread */ /* in the table with the same pthread id. */ /* This is OK, but we need a way to delete a specific one. */ STATIC void GC_delete_gc_thread(GC_thread t) { pthread_t id = t -> id; int hv = THREAD_TABLE_INDEX(id); GC_thread p = GC_threads[hv]; GC_thread prev = NULL; GC_ASSERT(I_HOLD_LOCK()); while (p != t) { prev = p; p = p -> next; } if (prev == 0) { GC_threads[hv] = p -> next; } else { GC_ASSERT(prev != &first_thread); prev -> next = p -> next; GC_dirty(prev); } # ifdef GC_DARWIN_THREADS mach_port_deallocate(mach_task_self(), p->stop_info.mach_thread); # endif GC_INTERNAL_FREE(p); # ifdef DEBUG_THREADS GC_log_printf("Deleted thread %p, n_threads= %d\n", (void *)id, GC_count_threads()); # endif } /* Return a GC_thread corresponding to a given pthread_t. */ /* Returns 0 if it's not there. */ /* Caller holds allocation lock or otherwise inhibits */ /* updates. */ /* If there is more than one thread with the given id we */ /* return the most recent one. */ GC_INNER GC_thread GC_lookup_thread(pthread_t id) { GC_thread p = GC_threads[THREAD_TABLE_INDEX(id)]; while (p != 0 && !THREAD_EQUAL(p -> id, id)) p = p -> next; return(p); } #ifndef GC_NO_FINALIZATION /* Called by GC_finalize() (in case of an allocation failure observed). */ GC_INNER void GC_reset_finalizer_nested(void) { GC_thread me = GC_lookup_thread(pthread_self()); me->finalizer_nested = 0; } /* Checks and updates the thread-local level of finalizers recursion. */ /* Returns NULL if GC_invoke_finalizers() should not be called by the */ /* collector (to minimize the risk of a deep finalizers recursion), */ /* otherwise returns a pointer to the thread-local finalizer_nested. */ /* Called by GC_notify_or_invoke_finalizers() only (the GC lock is */ /* held). */ GC_INNER unsigned char *GC_check_finalizer_nested(void) { GC_thread me = GC_lookup_thread(pthread_self()); unsigned nesting_level; # if defined(INCLUDE_LINUX_THREAD_DESCR) && defined(REDIRECT_MALLOC) /* As noted in GC_start_routine, an allocation may happen in */ /* GC_get_stack_base, causing GC_notify_or_invoke_finalizers */ /* to be called before the thread gets registered. */ if (EXPECT(NULL == me, FALSE)) return NULL; # endif nesting_level = me->finalizer_nested; if (nesting_level) { /* We are inside another GC_invoke_finalizers(). */ /* Skip some implicitly-called GC_invoke_finalizers() */ /* depending on the nesting (recursion) level. */ if (++me->finalizer_skipped < (1U << nesting_level)) return NULL; me->finalizer_skipped = 0; } me->finalizer_nested = (unsigned char)(nesting_level + 1); return &me->finalizer_nested; } #endif /* !GC_NO_FINALIZATION */ #if defined(GC_ASSERTIONS) && defined(THREAD_LOCAL_ALLOC) /* This is called from thread-local GC_malloc(). */ GC_bool GC_is_thread_tsd_valid(void *tsd) { GC_thread me; DCL_LOCK_STATE; LOCK(); me = GC_lookup_thread(pthread_self()); UNLOCK(); return (word)tsd >= (word)(&me->tlfs) && (word)tsd < (word)(&me->tlfs) + sizeof(me->tlfs); } #endif /* GC_ASSERTIONS && THREAD_LOCAL_ALLOC */ GC_API int GC_CALL GC_thread_is_registered(void) { pthread_t self = pthread_self(); GC_thread me; DCL_LOCK_STATE; LOCK(); me = GC_lookup_thread(self); UNLOCK(); return me != NULL && !(me -> flags & FINISHED); } static pthread_t main_pthread_id; static void *main_stack, *main_altstack; static word main_stack_size, main_altstack_size; GC_API void GC_CALL GC_register_altstack(void *stack, GC_word stack_size, void *altstack, GC_word altstack_size) { GC_thread me; pthread_t self = pthread_self(); DCL_LOCK_STATE; LOCK(); me = GC_lookup_thread(self); if (me != NULL) { me->stack = (ptr_t)stack; me->stack_size = stack_size; me->altstack = (ptr_t)altstack; me->altstack_size = altstack_size; } else { /* This happens if we are called before GC_thr_init. */ main_pthread_id = self; main_stack = stack; main_stack_size = stack_size; main_altstack = altstack; main_altstack_size = altstack_size; } UNLOCK(); } #ifdef CAN_HANDLE_FORK /* Prevent TSan false positive about the race during items removal */ /* from GC_threads. (The race cannot happen since only one thread */ /* survives in the child.) */ # ifdef CAN_CALL_ATFORK GC_ATTR_NO_SANITIZE_THREAD # endif static void store_to_threads_table(int hv, GC_thread me) { GC_threads[hv] = me; } /* Remove all entries from the GC_threads table, except the */ /* one for the current thread. We need to do this in the child */ /* process after a fork(), since only the current thread */ /* survives in the child. */ STATIC void GC_remove_all_threads_but_me(void) { pthread_t self = pthread_self(); int hv; for (hv = 0; hv < THREAD_TABLE_SZ; ++hv) { GC_thread p, next; GC_thread me = NULL; for (p = GC_threads[hv]; 0 != p; p = next) { next = p -> next; if (THREAD_EQUAL(p -> id, self) && me == NULL) { /* ignore dead threads with the same id */ me = p; p -> next = 0; # ifdef GC_DARWIN_THREADS /* Update thread Id after fork (it is OK to call */ /* GC_destroy_thread_local and GC_free_inner */ /* before update). */ me -> stop_info.mach_thread = mach_thread_self(); # endif # ifdef USE_TKILL_ON_ANDROID me -> kernel_id = gettid(); # endif # if defined(THREAD_LOCAL_ALLOC) && !defined(USE_CUSTOM_SPECIFIC) { int res; /* Some TLS implementations might be not fork-friendly, so */ /* we re-assign thread-local pointer to 'tlfs' for safety */ /* instead of the assertion check (again, it is OK to call */ /* GC_destroy_thread_local and GC_free_inner before). */ res = GC_setspecific(GC_thread_key, &me->tlfs); if (COVERT_DATAFLOW(res) != 0) ABORT("GC_setspecific failed (in child)"); } # endif } else { # ifdef THREAD_LOCAL_ALLOC if (!(p -> flags & FINISHED)) { /* Cannot call GC_destroy_thread_local here. The free */ /* lists may be in an inconsistent state (as thread p may */ /* be updating one of the lists by GC_generic_malloc_many */ /* or GC_FAST_MALLOC_GRANS when fork is invoked). */ /* This should not be a problem because the lost elements */ /* of the free lists will be collected during GC. */ GC_remove_specific_after_fork(GC_thread_key, p -> id); } # endif /* TODO: To avoid TSan hang (when updating GC_bytes_freed), */ /* we just skip explicit freeing of GC_threads entries. */ # if !defined(THREAD_SANITIZER) || !defined(CAN_CALL_ATFORK) if (p != &first_thread) GC_INTERNAL_FREE(p); # endif } } store_to_threads_table(hv, me); } } #endif /* CAN_HANDLE_FORK */ #ifdef USE_PROC_FOR_LIBRARIES GC_INNER GC_bool GC_segment_is_thread_stack(ptr_t lo, ptr_t hi) { int i; GC_thread p; GC_ASSERT(I_HOLD_LOCK()); # ifdef PARALLEL_MARK for (i = 0; i < GC_markers_m1; ++i) { if ((word)marker_sp[i] > (word)lo && (word)marker_sp[i] < (word)hi) return TRUE; # ifdef IA64 if ((word)marker_bsp[i] > (word)lo && (word)marker_bsp[i] < (word)hi) return TRUE; # endif } # endif for (i = 0; i < THREAD_TABLE_SZ; i++) { for (p = GC_threads[i]; p != 0; p = p -> next) { if (0 != p -> stack_end) { # ifdef STACK_GROWS_UP if ((word)p->stack_end >= (word)lo && (word)p->stack_end < (word)hi) return TRUE; # else /* STACK_GROWS_DOWN */ if ((word)p->stack_end > (word)lo && (word)p->stack_end <= (word)hi) return TRUE; # endif } } } return FALSE; } #endif /* USE_PROC_FOR_LIBRARIES */ #if (defined(HAVE_PTHREAD_ATTR_GET_NP) || defined(HAVE_PTHREAD_GETATTR_NP)) \ && defined(IA64) /* Find the largest stack_base smaller than bound. May be used */ /* to find the boundary between a register stack and adjacent */ /* immediately preceding memory stack. */ GC_INNER ptr_t GC_greatest_stack_base_below(ptr_t bound) { int i; GC_thread p; ptr_t result = 0; GC_ASSERT(I_HOLD_LOCK()); # ifdef PARALLEL_MARK for (i = 0; i < GC_markers_m1; ++i) { if ((word)marker_sp[i] > (word)result && (word)marker_sp[i] < (word)bound) result = marker_sp[i]; } # endif for (i = 0; i < THREAD_TABLE_SZ; i++) { for (p = GC_threads[i]; p != 0; p = p -> next) { if ((word)p->stack_end > (word)result && (word)p->stack_end < (word)bound) { result = p -> stack_end; } } } return result; } #endif /* IA64 */ #ifndef STAT_READ # define STAT_READ read /* If read is wrapped, this may need to be redefined to call */ /* the real one. */ #endif #ifdef GC_HPUX_THREADS # define GC_get_nprocs() pthread_num_processors_np() #elif defined(GC_OSF1_THREADS) || defined(GC_AIX_THREADS) \ || defined(GC_HAIKU_THREADS) || defined(GC_SOLARIS_THREADS) \ || defined(HURD) || defined(HOST_ANDROID) || defined(NACL) GC_INLINE int GC_get_nprocs(void) { int nprocs = (int)sysconf(_SC_NPROCESSORS_ONLN); return nprocs > 0 ? nprocs : 1; /* ignore error silently */ } #elif defined(GC_IRIX_THREADS) GC_INLINE int GC_get_nprocs(void) { int nprocs = (int)sysconf(_SC_NPROC_ONLN); return nprocs > 0 ? nprocs : 1; /* ignore error silently */ } #elif defined(GC_LINUX_THREADS) /* && !HOST_ANDROID && !NACL */ /* Return the number of processors. */ STATIC int GC_get_nprocs(void) { /* Should be "return sysconf(_SC_NPROCESSORS_ONLN);" but that */ /* appears to be buggy in many cases. */ /* We look for lines "cpu" in /proc/stat. */ # define PROC_STAT_BUF_SZ ((1 + MAX_MARKERS) * 100) /* should be enough */ /* No need to read the entire /proc/stat to get maximum cpu as */ /* - the requested lines are located at the beginning of the file; */ /* - the lines with cpu where N > MAX_MARKERS are not needed. */ char stat_buf[PROC_STAT_BUF_SZ+1]; int f; int result, i, len; f = open("/proc/stat", O_RDONLY); if (f < 0) { WARN("Could not open /proc/stat\n", 0); return 1; /* assume an uniprocessor */ } len = STAT_READ(f, stat_buf, sizeof(stat_buf)-1); /* Unlikely that we need to retry because of an incomplete read here. */ if (len < 0) { WARN("Failed to read /proc/stat, errno= %" WARN_PRIdPTR "\n", (signed_word)errno); close(f); return 1; } stat_buf[len] = '\0'; /* to avoid potential buffer overrun by atoi() */ close(f); result = 1; /* Some old kernels only have a single "cpu nnnn ..." */ /* entry in /proc/stat. We identify those as */ /* uniprocessors. */ for (i = 0; i < len - 4; ++i) { if (stat_buf[i] == '\n' && stat_buf[i+1] == 'c' && stat_buf[i+2] == 'p' && stat_buf[i+3] == 'u') { int cpu_no = atoi(&stat_buf[i + 4]); if (cpu_no >= result) result = cpu_no + 1; } } return result; } #elif defined(GC_DGUX386_THREADS) /* Return the number of processors, or i <= 0 if it can't be determined. */ STATIC int GC_get_nprocs(void) { int numCpus; struct dg_sys_info_pm_info pm_sysinfo; int status = 0; status = dg_sys_info((long int *) &pm_sysinfo, DG_SYS_INFO_PM_INFO_TYPE, DG_SYS_INFO_PM_CURRENT_VERSION); if (status < 0) /* set -1 for error */ numCpus = -1; else /* Active CPUs */ numCpus = pm_sysinfo.idle_vp_count; return(numCpus); } #elif defined(GC_DARWIN_THREADS) || defined(GC_FREEBSD_THREADS) \ || defined(GC_NETBSD_THREADS) || defined(GC_OPENBSD_THREADS) STATIC int GC_get_nprocs(void) { int mib[] = {CTL_HW,HW_NCPU}; int res; size_t len = sizeof(res); sysctl(mib, sizeof(mib)/sizeof(int), &res, &len, NULL, 0); return res; } #else /* E.g., GC_RTEMS_PTHREADS */ # define GC_get_nprocs() 1 /* not implemented */ #endif /* !GC_LINUX_THREADS && !GC_DARWIN_THREADS && ... */ #if defined(ARM32) && defined(GC_LINUX_THREADS) && !defined(NACL) /* Some buggy Linux/arm kernels show only non-sleeping CPUs in */ /* /proc/stat (and /proc/cpuinfo), so another data system source is */ /* tried first. Result <= 0 on error. */ STATIC int GC_get_nprocs_present(void) { char stat_buf[16]; int f; int len; f = open("/sys/devices/system/cpu/present", O_RDONLY); if (f < 0) return -1; /* cannot open the file */ len = STAT_READ(f, stat_buf, sizeof(stat_buf)); close(f); /* Recognized file format: "0\n" or "0-\n" */ /* The file might probably contain a comma-separated list */ /* but we do not need to handle it (just silently ignore). */ if (len < 2 || stat_buf[0] != '0' || stat_buf[len - 1] != '\n') { return 0; /* read error or unrecognized content */ } else if (len == 2) { return 1; /* an uniprocessor */ } else if (stat_buf[1] != '-') { return 0; /* unrecognized content */ } stat_buf[len - 1] = '\0'; /* terminate the string */ return atoi(&stat_buf[2]) + 1; /* skip "0-" and parse max_cpu_num */ } #endif /* ARM32 && GC_LINUX_THREADS && !NACL */ #if defined(CAN_HANDLE_FORK) && defined(THREAD_SANITIZER) # include "private/gc_pmark.h" /* for MS_NONE */ /* Workaround for TSan which does not notice that the GC lock */ /* is acquired in fork_prepare_proc(). */ GC_ATTR_NO_SANITIZE_THREAD static GC_bool collection_in_progress(void) { return GC_mark_state != MS_NONE; } #else # define collection_in_progress() GC_collection_in_progress() #endif /* We hold the GC lock. Wait until an in-progress GC has finished. */ /* Repeatedly RELEASES GC LOCK in order to wait. */ /* If wait_for_all is true, then we exit with the GC lock held and no */ /* collection in progress; otherwise we just wait for the current GC */ /* to finish. */ STATIC void GC_wait_for_gc_completion(GC_bool wait_for_all) { DCL_LOCK_STATE; # if !defined(THREAD_SANITIZER) || !defined(CAN_CALL_ATFORK) /* GC_lock_holder is accessed with the lock held, so there is no */ /* data race actually (unlike what is reported by TSan). */ GC_ASSERT(I_HOLD_LOCK()); # endif ASSERT_CANCEL_DISABLED(); if (GC_incremental && collection_in_progress()) { word old_gc_no = GC_gc_no; /* Make sure that no part of our stack is still on the mark stack, */ /* since it's about to be unmapped. */ while (GC_incremental && collection_in_progress() && (wait_for_all || old_gc_no == GC_gc_no)) { ENTER_GC(); GC_in_thread_creation = TRUE; GC_collect_a_little_inner(1); GC_in_thread_creation = FALSE; EXIT_GC(); UNLOCK(); sched_yield(); LOCK(); } } } #ifdef CAN_HANDLE_FORK /* Procedures called before and after a fork. The goal here is to make */ /* it safe to call GC_malloc() in a forked child. It's unclear that is */ /* attainable, since the single UNIX spec seems to imply that one */ /* should only call async-signal-safe functions, and we probably can't */ /* quite guarantee that. But we give it our best shot. (That same */ /* spec also implies that it's not safe to call the system malloc */ /* between fork() and exec(). Thus we're doing no worse than it.) */ IF_CANCEL(static int fork_cancel_state;) /* protected by allocation lock. */ # ifdef PARALLEL_MARK # ifdef THREAD_SANITIZER # if defined(GC_ASSERTIONS) && defined(CAN_CALL_ATFORK) STATIC void GC_generic_lock(pthread_mutex_t *); # endif GC_ATTR_NO_SANITIZE_THREAD static void wait_for_reclaim_atfork(void); # else # define wait_for_reclaim_atfork() GC_wait_for_reclaim() # endif # endif /* PARALLEL_MARK */ /* Called before a fork() */ #if defined(GC_ASSERTIONS) && defined(CAN_CALL_ATFORK) /* GC_lock_holder is updated safely (no data race actually). */ GC_ATTR_NO_SANITIZE_THREAD #endif static void fork_prepare_proc(void) { /* Acquire all relevant locks, so that after releasing the locks */ /* the child will see a consistent state in which monitor */ /* invariants hold. Unfortunately, we can't acquire libc locks */ /* we might need, and there seems to be no guarantee that libc */ /* must install a suitable fork handler. */ /* Wait for an ongoing GC to finish, since we can't finish it in */ /* the (one remaining thread in) the child. */ LOCK(); DISABLE_CANCEL(fork_cancel_state); /* Following waits may include cancellation points. */ # if defined(PARALLEL_MARK) if (GC_parallel) wait_for_reclaim_atfork(); # endif GC_wait_for_gc_completion(TRUE); # if defined(PARALLEL_MARK) if (GC_parallel) { # if defined(THREAD_SANITIZER) && defined(GC_ASSERTIONS) \ && defined(CAN_CALL_ATFORK) /* Prevent TSan false positive about the data race */ /* when updating GC_mark_lock_holder. */ GC_generic_lock(&mark_mutex); # else GC_acquire_mark_lock(); # endif } # endif GC_acquire_dirty_lock(); } /* Called in parent after a fork() (even if the latter failed). */ #if defined(GC_ASSERTIONS) && defined(CAN_CALL_ATFORK) GC_ATTR_NO_SANITIZE_THREAD #endif static void fork_parent_proc(void) { GC_release_dirty_lock(); # if defined(PARALLEL_MARK) if (GC_parallel) { # if defined(THREAD_SANITIZER) && defined(GC_ASSERTIONS) \ && defined(CAN_CALL_ATFORK) /* To match that in fork_prepare_proc. */ (void)pthread_mutex_unlock(&mark_mutex); # else GC_release_mark_lock(); # endif } # endif RESTORE_CANCEL(fork_cancel_state); UNLOCK(); } /* Called in child after a fork() */ #if defined(GC_ASSERTIONS) && defined(CAN_CALL_ATFORK) GC_ATTR_NO_SANITIZE_THREAD #endif static void fork_child_proc(void) { GC_release_dirty_lock(); # ifndef GC_DISABLE_INCREMENTAL GC_dirty_update_child(); # endif # ifdef PARALLEL_MARK if (GC_parallel) { # if defined(THREAD_SANITIZER) && defined(GC_ASSERTIONS) \ && defined(CAN_CALL_ATFORK) (void)pthread_mutex_unlock(&mark_mutex); # else GC_release_mark_lock(); # endif /* Turn off parallel marking in the child, since we are probably */ /* just going to exec, and we would have to restart mark threads. */ GC_parallel = FALSE; } # ifdef THREAD_SANITIZER /* TSan does not support threads creation in the child process. */ available_markers_m1 = 0; # endif # endif /* Clean up the thread table, so that just our thread is left. */ GC_remove_all_threads_but_me(); RESTORE_CANCEL(fork_cancel_state); UNLOCK(); /* Even though after a fork the child only inherits the single */ /* thread that called the fork(), if another thread in the parent */ /* was attempting to lock the mutex while being held in */ /* fork_child_prepare(), the mutex will be left in an inconsistent */ /* state in the child after the UNLOCK. This is the case, at */ /* least, in Mac OS X and leads to an unusable GC in the child */ /* which will block when attempting to perform any GC operation */ /* that acquires the allocation mutex. */ # ifdef USE_PTHREAD_LOCKS GC_ASSERT(I_DONT_HOLD_LOCK()); /* Reinitialize the mutex. It should be safe since we are */ /* running this in the child which only inherits a single thread. */ /* mutex_destroy() may return EBUSY, which makes no sense, but */ /* that is the reason for the need of the reinitialization. */ (void)pthread_mutex_destroy(&GC_allocate_ml); /* TODO: Probably some targets might need the default mutex */ /* attribute to be passed instead of NULL. */ if (0 != pthread_mutex_init(&GC_allocate_ml, NULL)) ABORT("pthread_mutex_init failed (in child)"); # endif } /* Routines for fork handling by client (no-op if pthread_atfork works). */ GC_API void GC_CALL GC_atfork_prepare(void) { if (!EXPECT(GC_is_initialized, TRUE)) GC_init(); if (GC_handle_fork <= 0) fork_prepare_proc(); } GC_API void GC_CALL GC_atfork_parent(void) { if (GC_handle_fork <= 0) fork_parent_proc(); } GC_API void GC_CALL GC_atfork_child(void) { if (GC_handle_fork <= 0) fork_child_proc(); } #endif /* CAN_HANDLE_FORK */ #ifdef INCLUDE_LINUX_THREAD_DESCR __thread int GC_dummy_thread_local; #endif #ifdef PARALLEL_MARK static void setup_mark_lock(void); static unsigned required_markers_cnt = 0; /* The default value (0) means the number of */ /* markers should be selected automatically. */ #endif /* PARALLEL_MARK */ GC_API void GC_CALL GC_set_markers_count(unsigned markers GC_ATTR_UNUSED) { # ifdef PARALLEL_MARK required_markers_cnt = markers < MAX_MARKERS ? markers : MAX_MARKERS; # endif } #ifndef DONT_USE_ATEXIT STATIC pthread_t GC_main_thread_id; GC_INNER GC_bool GC_is_main_thread(void) { GC_ASSERT(GC_thr_initialized); return THREAD_EQUAL(GC_main_thread_id, pthread_self()); } #endif /* !DONT_USE_ATEXIT */ GC_INNER void GC_thr_init(void) { GC_ASSERT(I_HOLD_LOCK()); if (GC_thr_initialized) return; GC_thr_initialized = TRUE; GC_ASSERT((word)&GC_threads % sizeof(word) == 0); # ifdef CAN_HANDLE_FORK /* Prepare for forks if requested. */ if (GC_handle_fork) { # ifdef CAN_CALL_ATFORK if (pthread_atfork(fork_prepare_proc, fork_parent_proc, fork_child_proc) == 0) { /* Handlers successfully registered. */ GC_handle_fork = 1; } else # endif /* else */ if (GC_handle_fork != -1) ABORT("pthread_atfork failed"); } # endif # ifdef INCLUDE_LINUX_THREAD_DESCR /* Explicitly register the region including the address */ /* of a thread local variable. This should include thread */ /* locals for the main thread, except for those allocated */ /* in response to dlopen calls. */ { ptr_t thread_local_addr = (ptr_t)(&GC_dummy_thread_local); ptr_t main_thread_start, main_thread_end; if (!GC_enclosing_mapping(thread_local_addr, &main_thread_start, &main_thread_end)) { ABORT("Failed to find mapping for main thread thread locals"); } else { /* main_thread_start and main_thread_end are initialized. */ GC_add_roots_inner(main_thread_start, main_thread_end, FALSE); } } # endif /* Add the initial thread, so we can stop it. */ { pthread_t self = pthread_self(); GC_thread t = GC_new_thread(self); if (t == NULL) ABORT("Failed to allocate memory for the initial thread"); # ifdef GC_DARWIN_THREADS t -> stop_info.mach_thread = mach_thread_self(); # else t -> stop_info.stack_ptr = GC_approx_sp(); # endif # ifndef DONT_USE_ATEXIT GC_main_thread_id = self; # endif t -> flags = DETACHED | MAIN_THREAD; if (THREAD_EQUAL(self, main_pthread_id)) { t -> stack = (ptr_t)main_stack; t -> stack_size = main_stack_size; t -> altstack = (ptr_t)main_altstack; t -> altstack_size = main_altstack_size; } } /* Set GC_nprocs and available_markers_m1. */ { char * nprocs_string = GETENV("GC_NPROCS"); GC_nprocs = -1; if (nprocs_string != NULL) GC_nprocs = atoi(nprocs_string); } if (GC_nprocs <= 0 # if defined(ARM32) && defined(GC_LINUX_THREADS) && !defined(NACL) && (GC_nprocs = GC_get_nprocs_present()) <= 1 /* Workaround for some Linux/arm kernels */ # endif ) { GC_nprocs = GC_get_nprocs(); } if (GC_nprocs <= 0) { WARN("GC_get_nprocs() returned %" WARN_PRIdPTR "\n", (signed_word)GC_nprocs); GC_nprocs = 2; /* assume dual-core */ # ifdef PARALLEL_MARK available_markers_m1 = 0; /* but use only one marker */ # endif } else { # ifdef PARALLEL_MARK { char * markers_string = GETENV("GC_MARKERS"); int markers = required_markers_cnt; if (markers_string != NULL) { markers = atoi(markers_string); if (markers <= 0 || markers > MAX_MARKERS) { WARN("Too big or invalid number of mark threads: %" WARN_PRIdPTR "; using maximum threads\n", (signed_word)markers); markers = MAX_MARKERS; } } else if (0 == markers) { /* Unless the client sets the desired number of */ /* parallel markers, it is determined based on the */ /* number of CPU cores. */ markers = GC_nprocs; # if defined(GC_MIN_MARKERS) && !defined(CPPCHECK) /* This is primarily for targets without getenv(). */ if (markers < GC_MIN_MARKERS) markers = GC_MIN_MARKERS; # endif if (markers > MAX_MARKERS) markers = MAX_MARKERS; /* silently limit the value */ } available_markers_m1 = markers - 1; } # endif } GC_COND_LOG_PRINTF("Number of processors: %d\n", GC_nprocs); # if defined(BASE_ATOMIC_OPS_EMULATED) && !defined(GC_DARWIN_THREADS) \ && !defined(GC_OPENBSD_UTHREADS) && !defined(NACL) \ && !defined(PLATFORM_STOP_WORLD) && !defined(SN_TARGET_PSP2) /* Ensure the process is running on just one CPU core. */ /* This is needed because the AO primitives emulated with */ /* locks cannot be used inside signal handlers. */ { cpu_set_t mask; int cpu_set_cnt = 0; int cpu_lowest_set = 0; int i = GC_nprocs > 1 ? GC_nprocs : 2; /* check at least 2 cores */ if (sched_getaffinity(0 /* current process */, sizeof(mask), &mask) == -1) ABORT_ARG1("sched_getaffinity failed", ": errno= %d", errno); while (i-- > 0) if (CPU_ISSET(i, &mask)) { cpu_lowest_set = i; cpu_set_cnt++; } if (0 == cpu_set_cnt) ABORT("sched_getaffinity returned empty mask"); if (cpu_set_cnt > 1) { CPU_ZERO(&mask); CPU_SET(cpu_lowest_set, &mask); /* select just one CPU */ if (sched_setaffinity(0, sizeof(mask), &mask) == -1) ABORT_ARG1("sched_setaffinity failed", ": errno= %d", errno); WARN("CPU affinity mask is set to %p\n", (word)1 << cpu_lowest_set); } } # endif /* BASE_ATOMIC_OPS_EMULATED */ # ifndef GC_DARWIN_THREADS GC_stop_init(); # endif # ifdef PARALLEL_MARK if (available_markers_m1 <= 0) { /* Disable parallel marking. */ GC_parallel = FALSE; GC_COND_LOG_PRINTF( "Single marker thread, turning off parallel marking\n"); } else { setup_mark_lock(); } # endif } /* Perform all initializations, including those that */ /* may require allocation. */ /* Called without allocation lock. */ /* Must be called before a second thread is created. */ /* Did we say it's called without the allocation lock? */ GC_INNER void GC_init_parallel(void) { # if defined(THREAD_LOCAL_ALLOC) DCL_LOCK_STATE; # endif if (parallel_initialized) return; parallel_initialized = TRUE; /* GC_init() calls us back, so set flag first. */ if (!GC_is_initialized) GC_init(); /* Initialize thread local free lists if used. */ # if defined(THREAD_LOCAL_ALLOC) LOCK(); GC_init_thread_local(&(GC_lookup_thread(pthread_self())->tlfs)); UNLOCK(); # endif } #ifndef GC_NO_PTHREAD_SIGMASK GC_API int WRAP_FUNC(pthread_sigmask)(int how, const sigset_t *set, sigset_t *oset) { sigset_t fudged_set; INIT_REAL_SYMS(); if (set != NULL && (how == SIG_BLOCK || how == SIG_SETMASK)) { int sig_suspend = GC_get_suspend_signal(); fudged_set = *set; GC_ASSERT(sig_suspend >= 0); if (sigdelset(&fudged_set, sig_suspend) != 0) ABORT("sigdelset failed"); set = &fudged_set; } return(REAL_FUNC(pthread_sigmask)(how, set, oset)); } #endif /* !GC_NO_PTHREAD_SIGMASK */ static GC_bool do_blocking_enter(GC_thread me) { # if defined(SPARC) || defined(IA64) ptr_t stack_ptr = GC_save_regs_in_stack(); /* TODO: regs saving already done by GC_with_callee_saves_pushed */ # elif defined(E2K) size_t stack_size; # endif GC_bool topOfStackUnset = FALSE; GC_ASSERT(I_HOLD_LOCK()); GC_ASSERT(!(me -> thread_blocked)); # ifdef SPARC me -> stop_info.stack_ptr = stack_ptr; # else me -> stop_info.stack_ptr = GC_approx_sp(); # endif # if defined(GC_DARWIN_THREADS) && !defined(DARWIN_DONT_PARSE_STACK) if (me -> topOfStack == NULL) { /* GC_do_blocking_inner is not called recursively, */ /* so topOfStack should be computed now. */ topOfStackUnset = TRUE; me -> topOfStack = GC_FindTopOfStack(0); } # endif # ifdef IA64 me -> backing_store_ptr = stack_ptr; # elif defined(E2K) GC_ASSERT(NULL == me -> backing_store_end); stack_size = GC_alloc_and_get_procedure_stack(&me->backing_store_end); me->backing_store_ptr = me->backing_store_end + stack_size; # endif me -> thread_blocked = (unsigned char)TRUE; /* Save context here if we want to support precise stack marking */ return topOfStackUnset; } static void do_blocking_leave(GC_thread me, GC_bool topOfStackUnset) { GC_ASSERT(I_HOLD_LOCK()); # if defined(CPPCHECK) GC_noop1((word)&me->thread_blocked); # endif me -> thread_blocked = FALSE; # ifdef E2K GC_ASSERT(me -> backing_store_end != NULL); /* Note that me->backing_store_end value here may differ from */ /* the one stored in this function previously. */ GC_INTERNAL_FREE(me -> backing_store_end); me -> backing_store_ptr = NULL; me -> backing_store_end = NULL; # endif # if defined(GC_DARWIN_THREADS) && !defined(DARWIN_DONT_PARSE_STACK) if (topOfStackUnset) me -> topOfStack = NULL; /* make topOfStack unset again */ # else (void)topOfStackUnset; # endif } /* Wrapper for functions that are likely to block for an appreciable */ /* length of time. */ GC_INNER void GC_do_blocking_inner(ptr_t data, void * context GC_ATTR_UNUSED) { struct blocking_data *d = (struct blocking_data *)data; GC_thread me; GC_bool topOfStackUnset; DCL_LOCK_STATE; LOCK(); me = GC_lookup_thread(pthread_self()); topOfStackUnset = do_blocking_enter(me); UNLOCK(); d -> client_data = (d -> fn)(d -> client_data); LOCK(); /* This will block if the world is stopped. */ # ifdef LINT2 { # ifdef GC_ASSERTIONS GC_thread saved_me = me; # endif /* The pointer to the GC thread descriptor should not be */ /* changed while the thread is registered but a static */ /* analysis tool might complain that this pointer value */ /* (obtained in the first locked section) is unreliable in */ /* the second locked section. */ me = GC_lookup_thread(pthread_self()); GC_ASSERT(me == saved_me); } # endif # if defined(GC_ENABLE_SUSPEND_THREAD) && !defined(GC_DARWIN_THREADS) \ && !defined(GC_OPENBSD_UTHREADS) && !defined(NACL) \ && !defined(PLATFORM_STOP_WORLD) && !defined(SN_TARGET_PSP2) /* Note: this code cannot be moved into do_blocking_leave() */ /* otherwise there could be a static analysis tool warning */ /* (false positive) about unlock without a matching lock. */ while (EXPECT((me -> stop_info.ext_suspend_cnt & 1) != 0, FALSE)) { word suspend_cnt = (word)(me -> stop_info.ext_suspend_cnt); /* read suspend counter (number) before unlocking */ UNLOCK(); GC_suspend_self_inner(me, suspend_cnt); LOCK(); } # endif do_blocking_leave(me, topOfStackUnset); UNLOCK(); } #if defined(GC_ENABLE_SUSPEND_THREAD) && !defined(GC_DARWIN_THREADS) \ && !defined(GC_OPENBSD_UTHREADS) && !defined(NACL) \ && !defined(PLATFORM_STOP_WORLD) && !defined(SN_TARGET_PSP2) /* Similar to GC_do_blocking_inner() but assuming the GC lock is held */ /* and fn is GC_suspend_self_inner. */ GC_INNER void GC_suspend_self_blocked(ptr_t thread_me, void * context GC_ATTR_UNUSED) { GC_thread me = (GC_thread)thread_me; GC_bool topOfStackUnset; DCL_LOCK_STATE; GC_ASSERT(I_HOLD_LOCK()); topOfStackUnset = do_blocking_enter(me); while ((me -> stop_info.ext_suspend_cnt & 1) != 0) { word suspend_cnt = (word)(me -> stop_info.ext_suspend_cnt); UNLOCK(); GC_suspend_self_inner(me, suspend_cnt); LOCK(); } do_blocking_leave(me, topOfStackUnset); } #endif GC_API void GC_CALL GC_set_stackbottom(void *gc_thread_handle, const struct GC_stack_base *sb) { GC_thread t = (GC_thread)gc_thread_handle; GC_ASSERT(sb -> mem_base != NULL); if (!EXPECT(GC_is_initialized, TRUE)) { GC_ASSERT(NULL == t); } else { GC_ASSERT(I_HOLD_LOCK()); if (NULL == t) /* current thread? */ t = GC_lookup_thread(pthread_self()); GC_ASSERT((t -> flags & FINISHED) == 0); GC_ASSERT(!(t -> thread_blocked) && NULL == t -> traced_stack_sect); /* for now */ if ((t -> flags & MAIN_THREAD) == 0) { t -> stack_end = (ptr_t)sb->mem_base; # ifdef IA64 t -> backing_store_end = (ptr_t)sb->reg_base; # endif return; } /* Otherwise alter the stack bottom of the primordial thread. */ } GC_stackbottom = (char*)sb->mem_base; # ifdef IA64 GC_register_stackbottom = (ptr_t)sb->reg_base; # endif } GC_API void * GC_CALL GC_get_my_stackbottom(struct GC_stack_base *sb) { pthread_t self = pthread_self(); GC_thread me; DCL_LOCK_STATE; LOCK(); me = GC_lookup_thread(self); /* The thread is assumed to be registered. */ if ((me -> flags & MAIN_THREAD) == 0) { sb -> mem_base = me -> stack_end; # ifdef IA64 sb -> reg_base = me -> backing_store_end; # elif defined(E2K) sb -> reg_base = NULL; # endif } else { sb -> mem_base = GC_stackbottom; # ifdef IA64 sb -> reg_base = GC_register_stackbottom; # elif defined(E2K) sb -> reg_base = NULL; # endif } UNLOCK(); return (void *)me; /* gc_thread_handle */ } /* GC_call_with_gc_active() has the opposite to GC_do_blocking() */ /* functionality. It might be called from a user function invoked by */ /* GC_do_blocking() to temporarily back allow calling any GC function */ /* and/or manipulating pointers to the garbage collected heap. */ GC_API void * GC_CALL GC_call_with_gc_active(GC_fn_type fn, void * client_data) { struct GC_traced_stack_sect_s stacksect; pthread_t self = pthread_self(); GC_thread me; # ifdef E2K size_t stack_size; # endif DCL_LOCK_STATE; LOCK(); /* This will block if the world is stopped. */ me = GC_lookup_thread(self); /* Adjust our stack bottom value (this could happen unless */ /* GC_get_stack_base() was used which returned GC_SUCCESS). */ if ((me -> flags & MAIN_THREAD) == 0) { GC_ASSERT(me -> stack_end != NULL); if ((word)me->stack_end HOTTER_THAN (word)(&stacksect)) me -> stack_end = (ptr_t)(&stacksect); } else { /* The original stack. */ if ((word)GC_stackbottom HOTTER_THAN (word)(&stacksect)) GC_stackbottom = (ptr_t)COVERT_DATAFLOW(&stacksect); } if (!me->thread_blocked) { /* We are not inside GC_do_blocking() - do nothing more. */ UNLOCK(); client_data = fn(client_data); /* Prevent treating the above as a tail call. */ GC_noop1(COVERT_DATAFLOW(&stacksect)); return client_data; /* result */ } # if defined(GC_ENABLE_SUSPEND_THREAD) && !defined(GC_DARWIN_THREADS) \ && !defined(GC_OPENBSD_UTHREADS) && !defined(NACL) \ && !defined(PLATFORM_STOP_WORLD) && !defined(SN_TARGET_PSP2) while (EXPECT((me -> stop_info.ext_suspend_cnt & 1) != 0, FALSE)) { word suspend_cnt = (word)(me -> stop_info.ext_suspend_cnt); UNLOCK(); GC_suspend_self_inner(me, suspend_cnt); LOCK(); } # endif /* Setup new "stack section". */ stacksect.saved_stack_ptr = me -> stop_info.stack_ptr; # ifdef IA64 /* This is the same as in GC_call_with_stack_base(). */ stacksect.backing_store_end = GC_save_regs_in_stack(); /* Unnecessarily flushes register stack, */ /* but that probably doesn't hurt. */ stacksect.saved_backing_store_ptr = me -> backing_store_ptr; # elif defined(E2K) GC_ASSERT(me -> backing_store_end != NULL); GC_INTERNAL_FREE(me -> backing_store_end); me -> backing_store_ptr = NULL; me -> backing_store_end = NULL; # endif stacksect.prev = me -> traced_stack_sect; me -> thread_blocked = FALSE; me -> traced_stack_sect = &stacksect; UNLOCK(); client_data = fn(client_data); GC_ASSERT(me -> thread_blocked == FALSE); GC_ASSERT(me -> traced_stack_sect == &stacksect); /* Restore original "stack section". */ # if defined(CPPCHECK) GC_noop1((word)me->traced_stack_sect); # endif # ifdef E2K (void)GC_save_regs_in_stack(); # endif LOCK(); me -> traced_stack_sect = stacksect.prev; # ifdef IA64 me -> backing_store_ptr = stacksect.saved_backing_store_ptr; # elif defined(E2K) GC_ASSERT(NULL == me -> backing_store_end); stack_size = GC_alloc_and_get_procedure_stack(&me->backing_store_end); me->backing_store_ptr = me->backing_store_end + stack_size; # endif me -> thread_blocked = (unsigned char)TRUE; me -> stop_info.stack_ptr = stacksect.saved_stack_ptr; UNLOCK(); return client_data; /* result */ } STATIC void GC_unregister_my_thread_inner(GC_thread me) { GC_ASSERT(I_HOLD_LOCK()); # ifdef DEBUG_THREADS GC_log_printf( "Unregistering thread %p, gc_thread= %p, n_threads= %d\n", (void *)me->id, (void *)me, GC_count_threads()); # endif GC_ASSERT(!(me -> flags & FINISHED)); # if defined(THREAD_LOCAL_ALLOC) GC_ASSERT(GC_getspecific(GC_thread_key) == &me->tlfs); GC_destroy_thread_local(&(me->tlfs)); # endif # ifdef NACL GC_nacl_shutdown_gc_thread(); GC_nacl_gc_thread_self = NULL; # endif # if defined(GC_HAVE_PTHREAD_EXIT) || !defined(GC_NO_PTHREAD_CANCEL) /* Handle DISABLED_GC flag which is set by the */ /* intercepted pthread_cancel or pthread_exit. */ if ((me -> flags & DISABLED_GC) != 0) { GC_dont_gc--; } # endif if (me -> flags & DETACHED) { GC_delete_thread(pthread_self()); } else { me -> flags |= FINISHED; } # if defined(THREAD_LOCAL_ALLOC) /* It is required to call remove_specific defined in specific.c. */ GC_remove_specific(GC_thread_key); # endif } GC_API int GC_CALL GC_unregister_my_thread(void) { pthread_t self = pthread_self(); GC_thread me; IF_CANCEL(int cancel_state;) DCL_LOCK_STATE; LOCK(); DISABLE_CANCEL(cancel_state); /* Wait for any GC that may be marking from our stack to */ /* complete before we remove this thread. */ GC_wait_for_gc_completion(FALSE); me = GC_lookup_thread(self); # ifdef DEBUG_THREADS GC_log_printf( "Called GC_unregister_my_thread on %p, gc_thread= %p\n", (void *)self, (void *)me); # endif GC_ASSERT(THREAD_EQUAL(me->id, self)); GC_unregister_my_thread_inner(me); RESTORE_CANCEL(cancel_state); UNLOCK(); return GC_SUCCESS; } /* Called at thread exit. */ /* Never called for main thread. That's OK, since it */ /* results in at most a tiny one-time leak. And */ /* linuxthreads doesn't reclaim the main threads */ /* resources or id anyway. */ GC_INNER_PTHRSTART void GC_thread_exit_proc(void *arg) { IF_CANCEL(int cancel_state;) DCL_LOCK_STATE; # ifdef DEBUG_THREADS GC_log_printf("Called GC_thread_exit_proc on %p, gc_thread= %p\n", (void *)((GC_thread)arg)->id, arg); # endif LOCK(); DISABLE_CANCEL(cancel_state); GC_wait_for_gc_completion(FALSE); GC_unregister_my_thread_inner((GC_thread)arg); RESTORE_CANCEL(cancel_state); UNLOCK(); } #if !defined(SN_TARGET_ORBIS) && !defined(SN_TARGET_PSP2) GC_API int WRAP_FUNC(pthread_join)(pthread_t thread, void **retval) { int result; GC_thread t; DCL_LOCK_STATE; INIT_REAL_SYMS(); LOCK(); t = (GC_thread)COVERT_DATAFLOW(GC_lookup_thread(thread)); /* This is guaranteed to be the intended one, since the thread id */ /* can't have been recycled by pthreads. */ UNLOCK(); result = REAL_FUNC(pthread_join)(thread, retval); # if defined(GC_FREEBSD_THREADS) /* On FreeBSD, the wrapped pthread_join() sometimes returns (what appears to be) a spurious EINTR which caused the test and real code to gratuitously fail. Having looked at system pthread library source code, I see how this return code may be generated. In one path of code, pthread_join() just returns the errno setting of the thread being joined. This does not match the POSIX specification or the local man pages thus I have taken the liberty to catch this one spurious return value properly conditionalized on GC_FREEBSD_THREADS. */ if (result == EINTR) result = 0; # endif if (result == 0) { LOCK(); /* Here the pthread thread id may have been recycled. */ /* Delete the thread from GC_threads (unless it has been */ /* registered again from the client thread key destructor). */ if ((t -> flags & FINISHED) != 0) GC_delete_gc_thread(t); UNLOCK(); } return result; } GC_API int WRAP_FUNC(pthread_detach)(pthread_t thread) { int result; GC_thread t; DCL_LOCK_STATE; INIT_REAL_SYMS(); LOCK(); t = (GC_thread)COVERT_DATAFLOW(GC_lookup_thread(thread)); UNLOCK(); result = REAL_FUNC(pthread_detach)(thread); if (result == 0) { LOCK(); t -> flags |= DETACHED; /* Here the pthread thread id may have been recycled. */ if ((t -> flags & FINISHED) != 0) { GC_delete_gc_thread(t); } UNLOCK(); } return result; } #endif /* !SN_TARGET_ORBIS && !SN_TARGET_PSP2 */ #ifndef GC_NO_PTHREAD_CANCEL /* We should deal with the fact that apparently on Solaris and, */ /* probably, on some Linux we can't collect while a thread is */ /* exiting, since signals aren't handled properly. This currently */ /* gives rise to deadlocks. The only workaround seen is to intercept */ /* pthread_cancel() and pthread_exit(), and disable the collections */ /* until the thread exit handler is called. That's ugly, because we */ /* risk growing the heap unnecessarily. But it seems that we don't */ /* really have an option in that the process is not in a fully */ /* functional state while a thread is exiting. */ GC_API int WRAP_FUNC(pthread_cancel)(pthread_t thread) { # ifdef CANCEL_SAFE GC_thread t; DCL_LOCK_STATE; # endif INIT_REAL_SYMS(); # ifdef CANCEL_SAFE LOCK(); t = GC_lookup_thread(thread); /* We test DISABLED_GC because pthread_exit could be called at */ /* the same time. (If t is NULL then pthread_cancel should */ /* return ESRCH.) */ if (t != NULL && (t -> flags & DISABLED_GC) == 0) { t -> flags |= DISABLED_GC; GC_dont_gc++; } UNLOCK(); # endif return REAL_FUNC(pthread_cancel)(thread); } #endif /* !GC_NO_PTHREAD_CANCEL */ #ifdef GC_HAVE_PTHREAD_EXIT GC_API GC_PTHREAD_EXIT_ATTRIBUTE void WRAP_FUNC(pthread_exit)(void *retval) { pthread_t self = pthread_self(); GC_thread me; DCL_LOCK_STATE; INIT_REAL_SYMS(); LOCK(); me = GC_lookup_thread(self); /* We test DISABLED_GC because someone else could call */ /* pthread_cancel at the same time. */ if (me != 0 && (me -> flags & DISABLED_GC) == 0) { me -> flags |= DISABLED_GC; GC_dont_gc++; } UNLOCK(); REAL_FUNC(pthread_exit)(retval); } #endif /* GC_HAVE_PTHREAD_EXIT */ GC_INNER GC_bool GC_in_thread_creation = FALSE; /* Protected by allocation lock. */ GC_INLINE void GC_record_stack_base(GC_thread me, const struct GC_stack_base *sb) { # ifndef GC_DARWIN_THREADS me -> stop_info.stack_ptr = (ptr_t)sb->mem_base; # endif me -> stack_end = (ptr_t)sb->mem_base; if (me -> stack_end == NULL) ABORT("Bad stack base in GC_register_my_thread"); # ifdef IA64 me -> backing_store_end = (ptr_t)sb->reg_base; # endif } STATIC GC_thread GC_register_my_thread_inner(const struct GC_stack_base *sb, pthread_t my_pthread) { GC_thread me; GC_in_thread_creation = TRUE; /* OK to collect from unknown thread. */ me = GC_new_thread(my_pthread); GC_in_thread_creation = FALSE; if (me == 0) ABORT("Failed to allocate memory for thread registering"); # ifdef GC_DARWIN_THREADS me -> stop_info.mach_thread = mach_thread_self(); # endif GC_record_stack_base(me, sb); # ifdef GC_EXPLICIT_SIGNALS_UNBLOCK /* Since this could be executed from a detached thread */ /* destructor, our signals might already be blocked. */ GC_unblock_gc_signals(); # endif return me; } GC_API void GC_CALL GC_allow_register_threads(void) { # ifdef GC_ASSERTIONS DCL_LOCK_STATE; /* Check GC is initialized and the current thread is registered. */ LOCK(); /* just to match that in win32_threads.c */ GC_ASSERT(GC_lookup_thread(pthread_self()) != 0); UNLOCK(); # endif INIT_REAL_SYMS(); /* to initialize symbols while single-threaded */ GC_init_lib_bounds(); GC_start_mark_threads(); set_need_to_lock(); } GC_API int GC_CALL GC_register_my_thread(const struct GC_stack_base *sb) { pthread_t self = pthread_self(); GC_thread me; DCL_LOCK_STATE; if (GC_need_to_lock == FALSE) ABORT("Threads explicit registering is not previously enabled"); LOCK(); me = GC_lookup_thread(self); if (0 == me) { me = GC_register_my_thread_inner(sb, self); # if defined(CPPCHECK) GC_noop1(me->flags); # endif me -> flags |= DETACHED; /* Treat as detached, since we do not need to worry about */ /* pointer results. */ # if defined(THREAD_LOCAL_ALLOC) GC_init_thread_local(&(me->tlfs)); # endif UNLOCK(); return GC_SUCCESS; } else if ((me -> flags & FINISHED) != 0) { /* This code is executed when a thread is registered from the */ /* client thread key destructor. */ # ifdef NACL GC_nacl_gc_thread_self = me; GC_nacl_initialize_gc_thread(); # endif # ifdef GC_DARWIN_THREADS /* Reinitialize mach_thread to avoid thread_suspend fail */ /* with MACH_SEND_INVALID_DEST error. */ me -> stop_info.mach_thread = mach_thread_self(); # endif GC_record_stack_base(me, sb); me -> flags &= ~FINISHED; /* but not DETACHED */ # ifdef GC_EXPLICIT_SIGNALS_UNBLOCK /* Since this could be executed from a thread destructor, */ /* our signals might be blocked. */ GC_unblock_gc_signals(); # endif # if defined(THREAD_LOCAL_ALLOC) GC_init_thread_local(&(me->tlfs)); # endif # if defined(GC_ENABLE_SUSPEND_THREAD) && !defined(GC_DARWIN_THREADS) \ && !defined(GC_OPENBSD_UTHREADS) && !defined(NACL) \ && !defined(PLATFORM_STOP_WORLD) && !defined(SN_TARGET_PSP2) if ((me -> stop_info.ext_suspend_cnt & 1) != 0) { GC_with_callee_saves_pushed(GC_suspend_self_blocked, (ptr_t)me); } # endif UNLOCK(); return GC_SUCCESS; } else { UNLOCK(); return GC_DUPLICATE; } } struct start_info { void *(*start_routine)(void *); void *arg; word flags; sem_t registered; /* 1 ==> in our thread table, but */ /* parent hasn't yet noticed. */ }; /* Called from GC_inner_start_routine(). Defined in this file to */ /* minimize the number of include files in pthread_start.c (because */ /* sem_t and sem_post() are not used in that file directly). */ GC_INNER_PTHRSTART GC_thread GC_start_rtn_prepare_thread( void *(**pstart)(void *), void **pstart_arg, struct GC_stack_base *sb, void *arg) { struct start_info * si = (struct start_info *)arg; pthread_t self = pthread_self(); GC_thread me; DCL_LOCK_STATE; # ifdef DEBUG_THREADS GC_log_printf("Starting thread %p, pid= %ld, sp= %p\n", (void *)self, (long)getpid(), (void *)&arg); # endif LOCK(); me = GC_register_my_thread_inner(sb, self); me -> flags = si -> flags; # if defined(THREAD_LOCAL_ALLOC) GC_init_thread_local(&(me->tlfs)); # endif UNLOCK(); *pstart = si -> start_routine; # ifdef DEBUG_THREADS GC_log_printf("start_routine= %p\n", (void *)(signed_word)(*pstart)); # endif *pstart_arg = si -> arg; sem_post(&(si -> registered)); /* Last action on si. */ /* OK to deallocate. */ return me; } #if !defined(SN_TARGET_ORBIS) && !defined(SN_TARGET_PSP2) STATIC void * GC_start_routine(void * arg) { # ifdef INCLUDE_LINUX_THREAD_DESCR struct GC_stack_base sb; # ifdef REDIRECT_MALLOC /* GC_get_stack_base may call pthread_getattr_np, which can */ /* unfortunately call realloc, which may allocate from an */ /* unregistered thread. This is unpleasant, since it might */ /* force heap growth (or, even, heap overflow). */ GC_disable(); # endif if (GC_get_stack_base(&sb) != GC_SUCCESS) ABORT("Failed to get thread stack base"); # ifdef REDIRECT_MALLOC GC_enable(); # endif return GC_inner_start_routine(&sb, arg); # else return GC_call_with_stack_base(GC_inner_start_routine, arg); # endif } GC_API int WRAP_FUNC(pthread_create)(pthread_t *new_thread, GC_PTHREAD_CREATE_CONST pthread_attr_t *attr, void *(*start_routine)(void *), void *arg) { int result; int detachstate; word my_flags = 0; struct start_info si; DCL_LOCK_STATE; /* This is otherwise saved only in an area mmapped by the thread */ /* library, which isn't visible to the collector. */ /* We resist the temptation to muck with the stack size here, */ /* even if the default is unreasonably small. That's the client's */ /* responsibility. */ INIT_REAL_SYMS(); if (!EXPECT(parallel_initialized, TRUE)) GC_init_parallel(); GC_init_lib_bounds(); if (sem_init(&si.registered, GC_SEM_INIT_PSHARED, 0) != 0) ABORT("sem_init failed"); si.start_routine = start_routine; si.arg = arg; LOCK(); if (!EXPECT(GC_thr_initialized, TRUE)) GC_thr_init(); # ifdef GC_ASSERTIONS { size_t stack_size = 0; if (NULL != attr) { if (pthread_attr_getstacksize(attr, &stack_size) != 0) ABORT("pthread_attr_getstacksize failed"); } if (0 == stack_size) { pthread_attr_t my_attr; if (pthread_attr_init(&my_attr) != 0) ABORT("pthread_attr_init failed"); if (pthread_attr_getstacksize(&my_attr, &stack_size) != 0) ABORT("pthread_attr_getstacksize failed"); (void)pthread_attr_destroy(&my_attr); } /* On Solaris 10, with default attr initialization, */ /* stack_size remains 0. Fudge it. */ if (0 == stack_size) { # ifndef SOLARIS WARN("Failed to get stack size for assertion checking\n", 0); # endif stack_size = 1000000; } GC_ASSERT(stack_size >= 65536); /* Our threads may need to do some work for the GC. */ /* Ridiculously small threads won't work, and they */ /* probably wouldn't work anyway. */ } # endif if (NULL == attr) { detachstate = PTHREAD_CREATE_JOINABLE; } else { if (pthread_attr_getdetachstate(attr, &detachstate) != 0) ABORT("pthread_attr_getdetachstate failed"); } if (PTHREAD_CREATE_DETACHED == detachstate) my_flags |= DETACHED; si.flags = my_flags; UNLOCK(); # ifdef DEBUG_THREADS GC_log_printf("About to start new thread from thread %p\n", (void *)pthread_self()); # endif # ifdef PARALLEL_MARK if (EXPECT(!GC_parallel && available_markers_m1 > 0, FALSE)) GC_start_mark_threads(); # endif set_need_to_lock(); result = REAL_FUNC(pthread_create)(new_thread, attr, GC_start_routine, &si); /* Wait until child has been added to the thread table. */ /* This also ensures that we hold onto the stack-allocated si until */ /* the child is done with it. */ if (0 == result) { IF_CANCEL(int cancel_state;) # ifdef DEBUG_THREADS /* new_thread is non-NULL because pthread_create requires it. */ GC_log_printf("Started thread %p\n", (void *)(*new_thread)); # endif DISABLE_CANCEL(cancel_state); /* pthread_create is not a cancellation point. */ while (0 != sem_wait(&si.registered)) { # if defined(GC_HAIKU_THREADS) /* To workaround some bug in Haiku semaphores. */ if (EACCES == errno) continue; # endif if (EINTR != errno) ABORT("sem_wait failed"); } RESTORE_CANCEL(cancel_state); } sem_destroy(&si.registered); return(result); } #endif /* !SN_TARGET_ORBIS && !SN_TARGET_PSP2 */ #if defined(USE_SPIN_LOCK) || !defined(NO_PTHREAD_TRYLOCK) /* Spend a few cycles in a way that can't introduce contention with */ /* other threads. */ #define GC_PAUSE_SPIN_CYCLES 10 STATIC void GC_pause(void) { int i; for (i = 0; i < GC_PAUSE_SPIN_CYCLES; ++i) { /* Something that's unlikely to be optimized away. */ # if defined(AO_HAVE_compiler_barrier) \ && !defined(BASE_ATOMIC_OPS_EMULATED) AO_compiler_barrier(); # else GC_noop1(i); # endif } } #endif #ifndef SPIN_MAX # define SPIN_MAX 128 /* Maximum number of calls to GC_pause before */ /* give up. */ #endif GC_INNER volatile GC_bool GC_collecting = FALSE; /* A hint that we're in the collector and */ /* holding the allocation lock for an */ /* extended period. */ #if (!defined(USE_SPIN_LOCK) && !defined(NO_PTHREAD_TRYLOCK)) \ || defined(PARALLEL_MARK) /* If we don't want to use the below spinlock implementation, either */ /* because we don't have a GC_test_and_set implementation, or because */ /* we don't want to risk sleeping, we can still try spinning on */ /* pthread_mutex_trylock for a while. This appears to be very */ /* beneficial in many cases. */ /* I suspect that under high contention this is nearly always better */ /* than the spin lock. But it's a bit slower on a uniprocessor. */ /* Hence we still default to the spin lock. */ /* This is also used to acquire the mark lock for the parallel */ /* marker. */ /* Here we use a strict exponential backoff scheme. I don't know */ /* whether that's better or worse than the above. We eventually */ /* yield by calling pthread_mutex_lock(); it never makes sense to */ /* explicitly sleep. */ /* #define LOCK_STATS */ /* Note that LOCK_STATS requires AO_HAVE_test_and_set. */ #ifdef LOCK_STATS volatile AO_t GC_spin_count = 0; volatile AO_t GC_block_count = 0; volatile AO_t GC_unlocked_count = 0; #endif STATIC void GC_generic_lock(pthread_mutex_t * lock) { #ifndef NO_PTHREAD_TRYLOCK unsigned pause_length = 1; unsigned i; if (0 == pthread_mutex_trylock(lock)) { # ifdef LOCK_STATS (void)AO_fetch_and_add1(&GC_unlocked_count); # endif return; } for (; pause_length <= SPIN_MAX; pause_length <<= 1) { for (i = 0; i < pause_length; ++i) { GC_pause(); } switch(pthread_mutex_trylock(lock)) { case 0: # ifdef LOCK_STATS (void)AO_fetch_and_add1(&GC_spin_count); # endif return; case EBUSY: break; default: ABORT("Unexpected error from pthread_mutex_trylock"); } } #endif /* !NO_PTHREAD_TRYLOCK */ # ifdef LOCK_STATS (void)AO_fetch_and_add1(&GC_block_count); # endif pthread_mutex_lock(lock); } #endif /* !USE_SPIN_LOCK || ... */ #if defined(AO_HAVE_char_load) && !defined(BASE_ATOMIC_OPS_EMULATED) # define is_collecting() \ ((GC_bool)AO_char_load((unsigned char *)&GC_collecting)) #else /* GC_collecting is a hint, a potential data race between */ /* GC_lock() and ENTER/EXIT_GC() is OK to ignore. */ # define is_collecting() GC_collecting #endif #if defined(USE_SPIN_LOCK) /* Reasonably fast spin locks. Basically the same implementation */ /* as STL alloc.h. This isn't really the right way to do this. */ /* but until the POSIX scheduling mess gets straightened out ... */ GC_INNER volatile AO_TS_t GC_allocate_lock = AO_TS_INITIALIZER; # define low_spin_max 30 /* spin cycles if we suspect uniprocessor */ # define high_spin_max SPIN_MAX /* spin cycles for multiprocessor */ static volatile AO_t spin_max = low_spin_max; static volatile AO_t last_spins = 0; /* A potential data race between */ /* threads invoking GC_lock which reads */ /* and updates spin_max and last_spins */ /* could be ignored because these */ /* variables are hints only. */ GC_INNER void GC_lock(void) { unsigned my_spin_max; unsigned my_last_spins; unsigned i; if (AO_test_and_set_acquire(&GC_allocate_lock) == AO_TS_CLEAR) { return; } my_spin_max = (unsigned)AO_load(&spin_max); my_last_spins = (unsigned)AO_load(&last_spins); for (i = 0; i < my_spin_max; i++) { if (is_collecting() || GC_nprocs == 1) goto yield; if (i < my_last_spins/2) { GC_pause(); continue; } if (AO_test_and_set_acquire(&GC_allocate_lock) == AO_TS_CLEAR) { /* * got it! * Spinning worked. Thus we're probably not being scheduled * against the other process with which we were contending. * Thus it makes sense to spin longer the next time. */ AO_store(&last_spins, (AO_t)i); AO_store(&spin_max, (AO_t)high_spin_max); return; } } /* We are probably being scheduled against the other process. Sleep. */ AO_store(&spin_max, (AO_t)low_spin_max); yield: for (i = 0;; ++i) { if (AO_test_and_set_acquire(&GC_allocate_lock) == AO_TS_CLEAR) { return; } # define SLEEP_THRESHOLD 12 /* Under Linux very short sleeps tend to wait until */ /* the current time quantum expires. On old Linux */ /* kernels nanosleep (<= 2 ms) just spins. */ /* (Under 2.4, this happens only for real-time */ /* processes.) We want to minimize both behaviors */ /* here. */ if (i < SLEEP_THRESHOLD) { sched_yield(); } else { struct timespec ts; if (i > 24) i = 24; /* Don't wait for more than about 15 ms, */ /* even under extreme contention. */ ts.tv_sec = 0; ts.tv_nsec = 1 << i; nanosleep(&ts, 0); } } } #elif defined(USE_PTHREAD_LOCKS) # ifndef NO_PTHREAD_TRYLOCK GC_INNER void GC_lock(void) { if (1 == GC_nprocs || is_collecting()) { pthread_mutex_lock(&GC_allocate_ml); } else { GC_generic_lock(&GC_allocate_ml); } } # elif defined(GC_ASSERTIONS) GC_INNER void GC_lock(void) { pthread_mutex_lock(&GC_allocate_ml); } # endif #endif /* !USE_SPIN_LOCK && USE_PTHREAD_LOCKS */ #ifdef PARALLEL_MARK # ifdef GC_ASSERTIONS STATIC unsigned long GC_mark_lock_holder = NO_THREAD; # define SET_MARK_LOCK_HOLDER \ (void)(GC_mark_lock_holder = NUMERIC_THREAD_ID(pthread_self())) # define UNSET_MARK_LOCK_HOLDER \ do { \ GC_ASSERT(GC_mark_lock_holder \ == NUMERIC_THREAD_ID(pthread_self())); \ GC_mark_lock_holder = NO_THREAD; \ } while (0) # else # define SET_MARK_LOCK_HOLDER (void)0 # define UNSET_MARK_LOCK_HOLDER (void)0 # endif /* !GC_ASSERTIONS */ static pthread_cond_t builder_cv = PTHREAD_COND_INITIALIZER; static void setup_mark_lock(void) { # ifdef GLIBC_2_19_TSX_BUG pthread_mutexattr_t mattr; int glibc_minor = -1; int glibc_major = GC_parse_version(&glibc_minor, gnu_get_libc_version()); if (glibc_major > 2 || (glibc_major == 2 && glibc_minor >= 19)) { /* TODO: disable this workaround for glibc with fixed TSX */ /* This disables lock elision to workaround a bug in glibc 2.19+ */ if (0 != pthread_mutexattr_init(&mattr)) { ABORT("pthread_mutexattr_init failed"); } if (0 != pthread_mutexattr_settype(&mattr, PTHREAD_MUTEX_NORMAL)) { ABORT("pthread_mutexattr_settype failed"); } if (0 != pthread_mutex_init(&mark_mutex, &mattr)) { ABORT("pthread_mutex_init failed"); } (void)pthread_mutexattr_destroy(&mattr); } # endif } GC_INNER void GC_acquire_mark_lock(void) { # if defined(NUMERIC_THREAD_ID_UNIQUE) && !defined(THREAD_SANITIZER) GC_ASSERT(GC_mark_lock_holder != NUMERIC_THREAD_ID(pthread_self())); # endif GC_generic_lock(&mark_mutex); SET_MARK_LOCK_HOLDER; } GC_INNER void GC_release_mark_lock(void) { UNSET_MARK_LOCK_HOLDER; if (pthread_mutex_unlock(&mark_mutex) != 0) { ABORT("pthread_mutex_unlock failed"); } } /* Collector must wait for a freelist builders for 2 reasons: */ /* 1) Mark bits may still be getting examined without lock. */ /* 2) Partial free lists referenced only by locals may not be scanned */ /* correctly, e.g. if they contain "pointer-free" objects, since the */ /* free-list link may be ignored. */ STATIC void GC_wait_builder(void) { ASSERT_CANCEL_DISABLED(); UNSET_MARK_LOCK_HOLDER; if (pthread_cond_wait(&builder_cv, &mark_mutex) != 0) { ABORT("pthread_cond_wait failed"); } GC_ASSERT(GC_mark_lock_holder == NO_THREAD); SET_MARK_LOCK_HOLDER; } GC_INNER void GC_wait_for_reclaim(void) { GC_acquire_mark_lock(); while (GC_fl_builder_count > 0) { GC_wait_builder(); } GC_release_mark_lock(); } # if defined(CAN_HANDLE_FORK) && defined(THREAD_SANITIZER) /* Identical to GC_wait_for_reclaim() but with the no_sanitize */ /* attribute as a workaround for TSan which does not notice that */ /* the GC lock is acquired in fork_prepare_proc(). */ GC_ATTR_NO_SANITIZE_THREAD static void wait_for_reclaim_atfork(void) { GC_acquire_mark_lock(); while (GC_fl_builder_count > 0) GC_wait_builder(); GC_release_mark_lock(); } # endif /* CAN_HANDLE_FORK && THREAD_SANITIZER */ GC_INNER void GC_notify_all_builder(void) { GC_ASSERT(GC_mark_lock_holder == NUMERIC_THREAD_ID(pthread_self())); if (pthread_cond_broadcast(&builder_cv) != 0) { ABORT("pthread_cond_broadcast failed"); } } GC_INNER void GC_wait_marker(void) { ASSERT_CANCEL_DISABLED(); GC_ASSERT(GC_parallel); UNSET_MARK_LOCK_HOLDER; if (pthread_cond_wait(&mark_cv, &mark_mutex) != 0) { ABORT("pthread_cond_wait failed"); } GC_ASSERT(GC_mark_lock_holder == NO_THREAD); SET_MARK_LOCK_HOLDER; } GC_INNER void GC_notify_all_marker(void) { GC_ASSERT(GC_parallel); if (pthread_cond_broadcast(&mark_cv) != 0) { ABORT("pthread_cond_broadcast failed"); } } #endif /* PARALLEL_MARK */ #ifdef PTHREAD_REGISTER_CANCEL_WEAK_STUBS /* Workaround "undefined reference" linkage errors on some targets. */ EXTERN_C_BEGIN extern void __pthread_register_cancel(void) __attribute__((__weak__)); extern void __pthread_unregister_cancel(void) __attribute__((__weak__)); EXTERN_C_END void __pthread_register_cancel(void) {} void __pthread_unregister_cancel(void) {} #endif #endif /* GC_PTHREADS */